Map types merge instead of update

[ijcd]

There are some semantic conflicts between rethinkdb default behavior on update and Ecto integration tests that will need to be resolved:

See discussion here:

hamiltop/rethinkdb-elixir#115

[redrabbit]

@ijcd, can you elaborate on the issue here?

[ijcd]

It's been quite some time since I was looking at this, but the other thread has the details. Basically, there is a conflict between what ecto and rethink do with merging nested data.